A magnetic angle sensor may be used to detect a rotational position or movement of a shaft. Typically, a permanent magnet is attached to a rotatable shaft and a single magnetic field sensor is placed on the rotation axis and adjacent to the magnet.
A disadvantage of known solutions is that they are very sensitive to magnetic disturbances. For example, if the magnet generates a field of, e.g., 45 mT at the sensor elements, a magnetic disturbance amounting to, e.g., 3 mT (in a worst case direction perpendicular to the axis and orthogonal to the field of the magnet) leads to an error amounting to 3.8° (arctan( 3/45)=3.8°), which is generally not acceptable.